Conventional methods of screening compounds for potential efficacy of oral care agents against bacteria typically assess the efficacy of test compounds and compositions in a suspension culture of defined species of bacteria, measuring bacterial proliferation as a function of optical density (OD) in the presence and absence of the test agent, over a short period of time, following a brief exposure to the test agent.
Such assays are very effective to identify potent and fast-acting antibacterial agents, but are poorly suited to identifying optimal antibacterial agents when the agents would have repeated application over longer periods of time (e.g., by daily or twice daily brushing or rinsing).
Moreover, activity against defined microorganisms in suspension culture may not adequately measure activity against the natural microflora, comprising a diversity of species in a biofilm. Bacteria in a biofilm are developmentally and phenotypically different from genetically identical bacteria in a free-floating suspension, and may react differently to antibacterial agents.
Therefore, there is a need for improved assays for identifying and evaluating antibacterial agents effective against oral biofilms.